Poultry litter (Wastes)
In agriculture, poultry litter or broiler litter is a mixture of poultry excreta, spilled feed, feathers, and material used as bedding in poultry operations. This term is also used to refer to unused bedding materials. Poultry litter is used in confinement buildings used for raising broilers, turkeys and other birds. Common bedding materials include wood shavings, sawdust, peanut hulls, shredded sugar cane, straw, and other dry, absorbent, low-cost organic materials. Sand is also occasionally used as bedding. The bedding materials help absorb moisture, limiting the production of ammonia and harmful pathogens. The materials used for bedding can also have a significant impact on carcass quality and bird performance.
There are specific practices that must be followed to properly maintain the litter and maximize the health and productivity of the flocks raised on it. Many factors must be considered in successful litter management including time of the year, depth of the litter, floor space per bird, feeding practices, disease, the kind of floor, ventilation, watering devices, litter amendments, and even the potential fertilizer value of the litter after it is removed from the house. Most poultry are grown on dirt floors with some type of bedding material. Concrete floors and some specialized raised flooring are used at some facilities. In many areas of the country, shavings from pine or other soft woods have historically been the bedding of choice for poultry production. Regionally, other materials have been the bedding material of choice due to regional cost and availability, such as rice hulls in the lower Mississippi River poultry production areas of Arkansas and Mississippi.
Disposal and Re-use
Broilers have on average a 47-day growout period, during which the typical broiler chicken will generate about two pounds of litter, if you add the manure and bedding materials. Actual manure generation will be lower because it is only a fractional component of litter. This translates to an average of about .7 ounce per day per bird, varying considerably over the life of the bird. This means that a single broiler house, which can contain well over 20,000 birds can generate over 40,000 lbs of litter per flock.
Historically, applications for used poultry litter have included land application as a fertilizer for crops or pastures, potting material for the greenhouse and plant container industries, or occasionally as feed for cattle. Recently there has been an upsurge in the use of poultry litter as a bio-fuel source for electrical cogeneration and gasification.
Use as Fertilizer
Poultry litter’s traditional use is as fertilizer. As with other manures, the fertilizing value of poultry litter is excellent, but it is less concentrated than chemical fertilizers, giving it a relatively low value per ton. This makes it uneconomical to ship long distances, and it tends to lose its nitrogen value fairly quickly. Extracting its value requires that it be used on nearby farms. This limits its resale value in regions where there are more poultry farms than suitable nearby farmland.
Use as Cattle Feed
Traditionally used as fertilizer, it is now also used as a livestock feed as a cost-saving measure compared with other feedstock materials, particularly for beef animals.
Prior to 1967, the use of poultry litter as cattle feed was unregulated but that year the FDA issued a policy statement that poultry litter offered in interstate commerce as animal feed was adulterated, effectively banning the practice. In 1980, FDA reversed this policy and passed regulation of litter to the states. In December 2003, in response to the detection of bovine spongiform encephalopathy (mad cow disease) in a cow in the state of Washington, the FDA announced plans to put in place a poultry litter ban. Because poultry litter can contain recycled cattle proteins as either spilled feed or feed that has passed through the avian gut, the FDA was concerned that feeding litter would be a pathway for spreading mad cow disease. In 2004, FDA decided to take a more comprehensive approach to BSE that would remove the most infectious proteins from all animal feeds. The FDA decided at this point that a litter ban was unnecessary in part based on comments by the North American Rendering Industry (http://www.fda.gov/ohrms/dockets/dailys/03/Feb03/020603/8004e16b.html). In 2005, the FDA published a proposed rule that did not include a litter ban and in 2008 the final rule did not include the ban either.
Use as Fuel
There are currently several electrical generating plants in the UK, and recently in the US, that are utilizing poultry and turkey litter as their primary fuel. Most of these plants were developed by Energy Power Resources (in the UK), or by their US subsidiary, Fibrowatt USA. Operating plants include Thetford (38.5 MWe), Eye (12.7 MWe), Westfield (9.8 MWe), and Benson (55 MWe).
On a smaller scale, poultry litter is used in Ireland as a biomass energy source. This system uses the poultry litter as a fuel to heat the broiler houses for the next batch of poultry being grown thus removing the need for LPG gas or other fossil fuels.
Some companies such as Advanced Fibers & Powders are also developing gasification technologies to utilize poultry litter as a fuel for electrical and heating applications, along with producing valuable by-products including activated carbons and fertilizers.